In order to quantitate a reaction amount of an enzyme which acts on a substrate in a specimen or an amount of the substrate by degree of color generation depending on a reagent which is colored by the enzyme or substrate, a microbiological chip has been used. In this regard, specific substrate selectivity of the enzyme is utilized by using a trace amount like μL order of a test sample such as blood, urine and the like, which are the specimen originated from a biological object. Further, when a quantitative analysis of a substrate amount by converting an enzyme reaction amount into an electric signal by using a membrane including the enzyme and electrodes, DNA extraction and PCR amplification (polymerase chain reaction amplification) thereof, ion concentration measurement, microsynthesis of nucleic acid, saccharide, protein or peptide and the like are conducted in μM order, a microreactor chip has been used.
A microchemical chip such as the microbiological chip and microreactor chip has a channel-shaped micro flow path having tens to hundreds μm in width as a reaction channel which mixes, reacts, divides and detects the liquid specimen and a reagent which are pumped and flowed by pressurizing. When the liquid specimen and the reagent are mixed and reacted, the liquid specimen which flows in the micro flow path is flowed only in one direction, stopped and held in a reaction cistern. Such the flow of the liquid specimen has to be controlled.
A micro valve used in control of the above flow is disclosed in Patent Document 1. The micro valve disclosed therein comprises a valve chamber formed into a half way of a line of a flow path which flows a liquid such as a liquid specimen; a valve made from silicone rubber which partitions the valve chamber into two chambers; and a pressure chamber formed on a location corresponding to be located immediately above the valve chamber. According to the micro valve, the valve is closed by pressurization of the valve chamber through flow-in of pressurized air or is opened by depressurization of the valve chamber through vacuuming up air and thus, the flow path is opened and occluded. In the micro valve, since the volume of the two chambers is mutually different by the biased location of the valve in the valve chamber, difference in pressure of the fluid which is held therein may be utilized. Thereby a function of a check-valve may be given to the micro valve.
According to the micro valve of Patent Document 1, in order to open and close the valve, a motive power source such as a pump or a piezoelectric material, which directly pressurizes or depressurizes the valve chamber from above, is essential. Further when the function of the check-valve is given to the micro valve, the valve chamber having a large volume is required. A structure of the micro valve therefore has been complexed. Furthermore because design of a microchemical chip is restricted by a large amount of the valve chamber, miniaturization thereof has been difficult. In addition, the liquid specimen and the reagent are held in the valve chamber having the large volume, and are not smoothly flowed. Quick analysis and measurement thereof have been difficult.